Treatment of iron sulphide-bearing material



of difiere Patented July l1, 'i933 hieraan PATENT-f orrlcu RAYMOND 1i'. BACON, OF kBRONXVILLE, .AND HENRY T. HOTCHKISS, JR., OF NEW R-GHELLE, NEW YORK; SAD) HOTCHKISS, JR., ASSEGNOR TO SAD BACON TREATMENT'OF IRON SULPHIDE-BEARING MATERIAL Appncation mea February 25, 1930. serial No. 431,134.

This invention relates to the krecovery of sulphur and has for an object the provision of an improved process for,V recovering sulphur from heavy meta-l sulphide ores. More particularly, the invention contemplates the provision of an improved process *fory recovering sulphur from materials containing one or more sulphides of iron. The invention further contemplates the provision of an im-v proved process for treating heavy metal sulf phide ores such, for example, as ore containingr sulphides of iron, copper and nickel.

rihe process ofthe present inventionin? volves the treatment of ore or other metallurgical. raw materials or products containing pyrites or other sulphi des of iron, alone or in combination with sulphides of other heavy metals, such for example, as copper and nickel, with a reagent such chlorine, sulphuryl chloride or sulphur chloride for the purpose of obtaining free sulphur and/or sepa-rating iron from the mass of material undergoing treatment.

ln carrying out a process in accordance with the present invention, a quantity of the material to he treated is subjected to the action of a chlorinating agent under such conditions that free sulphur and ferric chloride are produced and vaporized. The vaporized sulphur is collected and the ferrie chloride isV utilizan Lor tr ,1 additional quantities of sulp material to produce a product in which ferrous chloride is concentrated'. The ferrous chloride concentrate is approriately treated to recover chlorine which is ed to the process.

`M sie process may be conveniently conducted by passing` the sulphide-bearing matcrial progressively through reaction Zones nt temperatures. According to the preferred process of the invention, the iron sulphide-bearing material is hrst introduced into a reaction Zone of relatively7 high temperature and passed progressively through .reaction zones of lower temperatures. .The process is controlled that ferrous chloride is produced in the high temperature reaction Y the higher temperature reaction zones, the

sulphur vapor ultimately being collected as free sulphur, and the ferrie chloride reactingy reagent and iron sulphide-bearing material are introduced at appropriate points.

The invention will be better understood from a consideration ofthe accompanying lowsheet and the following description of a process involving the treatment of ore containing sulphides lof iron, copper, andV nickel with chlorine. i

The ore to be treated is introduced in a dry, finely divided condition into the interior of a rotary reaction chamber having charging means at one end and discharging means at the other end. An opening or passage to permit the` outward passage of sulphur vapors and other gases is provided near the charging end. The temperature withinA the reaction chamber is so regulated that it gradually increases from the normal atmospheric temperature at the charging end to a maximum temperature of about 5500 C. .at point about midway between the two ends, and gradually decreases from theregion of maximum temperature to about 300 C. at the discharge end. The opening or passage for ber and the region of maximum temperature where the temperature within thecha-mber is about 450o C. or slightly lower.

The ore, preferably ground to provide particles sufficiently small to pass a 10G-mesh screen in order that intimate contact of the chlorine with the sulphide compounds may be obtained, is introduced into the reaction chamber at the charging end. Chlorine is introduced into the reaction chamber at the discharge end.

The process is conducted as a batch process, the discharge end of the chamber being closed. The ore may be fed to the chamber continuously until the desired concentration has been effected, or the ore may be fed to the reaction Achamber until a predetermined amount has been introduced.

When ore is lirstintroducedinto the reaction chamber, no chlorine is introduced until the ore reaches or passes the zone of maximum temperature. As the ore reaches the Zone of maximum temperf-iture, the chlorine may be admitted, slowly at first, and in gradually increasing amounts as the ore and chlorinated material progress through the chamber. Chlorine may be admitted at any desired maximum rate. rlhe rate at which chlorine is admitted and the amount of chlorine admitted will be determined by the rate of feeding of orc int-o the reaction Zones and the amount of ore to be treated.

Duringl the course of the process, the chlorine first reacts with the sulphides of iron, copper and nickel to produce free sulphur, ferrous chloride and the chlorides of copper and nickel. lhe free sulphur is vaporized and passes out of the reaction chamber to suitable collectingandl condensin apparatus. As the reaction chamber is rotated, the ferrous chloride-bearing material moves eradually toward the discharge end and fresh orc is moved into the Zone of maximum temperature. As the ferrous chloride-bearir:frA malicrial moves toward the discharge end the chlo rine reacts with the ferrous chloride and oxi` dizes it to ferrie chloride. The ferrie chloride produced is vaporized andthe resulting vapor is sivept along With the chlorine. toward the zone of maximum temperature. The ferrie chloride comes into contact with fresh. or partially chlorinated sulphiele-bearing ma terial and is reduced to ferrous chloride.

rljhe process is so conducted and controlled that'iron compounds are Substantially completely eliminated from the material in the discharge end portion of the reaction chamber and ferrous chloride isconcentrated in the adjoining' portion of the reaction chamber. rlfhe material in the discharge end portion of the reaction chamber will consist substantiallvv entirely of nickel and copper chlorides and ganfgue materials which may be present in the original'ore.

W hen the orc is fed continuously during; the course of a process. the admission of ore and chlorine may be discontinued when the presence of considerable ferrie chloride in the. issuing sulphur vapor indicates that insufficient fresh ore is being moved into the reaction zones to react With the ferrie chloride produced. or when the operations have been conducted for a predetermined length of time.

When the ore is fed to the reaction chamber only until a predetermined amount has been admitted, the admission of chlorine may be discontinued when the last portion of the ore reaches the zone of maximum temperature. The process may be so conducted that satisfactory concentration ivill have been effected at that time.

in the case of continuous feeding, at the completion of the chlorination treatment, the iron-free material containing chlorides of tween the charging` end and the zone of mav-` imum temperature, and the ferrous chloridebearmg material. Will be concentrated 1n the intermediate portion of the reaction chainl ber.

-Upon thc completion of a chlorination process involvinp tht-:admission of a predetermined amount or ore, the iron-free material Will be segregated in the discharge end portion of the reaction chamber, and the ferrous chloride-bearing; material will be concentrated in the adjoining` portion of the chamber. The ch argine,` end portion of the chamber will be empty.

TaWhen the admission of chlorine has been discontinued the discharge end of the reaction chamber may be opened. Rotation of the reaction chamber will cause the cont-ents to be discharged. The iron-free material containing' chlorides of copper and nickel is discharged and collected first. While the iron-free material is beine; discharged the ferrous chloride concentrate is being' moved toward the discharge end. After the ironfree material has been discharged and collected, the ferrous chloride concentrate 'is discharged and collected separately.

llVhen the ferrous chloride concentrate has been discharged, treatment of a fresh batch of ore is commenced.

rlhe ferrous chloride concentrate is subjected to the action of air at a temperature of 7000 C. to 5500o C. to recover chlorine. The treatment of the ferrous chloride concentrate is preferably so conducted that free chlorine is produced. The chlorine thus produced is utilized for treatin n the fresh batch of ore. inert gases, such as nitrogen, which are introduced into the system during' the `treatment of the ferrous chloride concentrate -with air are eliminated when the free sulphur iroduced is condensed.

A source of fresh chlorine is provided to compensate for losses due to leakage and the formation of nickel and copper chlorides.

The iron-free material may be treated in any suitable manner to recover the nickel and copper.

Ne claim:

1. The method of treating iron sulphidebearing material which comprises, contacting' a chlorinatinp; agent With said material at temperatures Which progressively increase as less chlorinated portions of the iron sulphide-bearing material come in Contact with chlorinating agent.

2. The method of treating iron sulphidebearinfr material Which comprises.y bringing a chlorinatinp; agent in contact with. said material at temperatures which progressively increase as less chlorinated portions of the material come in contact with chlorinating agent, said temperatures increasing from a point above the boiling temperature of ferric chloride to a point further above the boiling temperature of ferrie chloride but below the boiling temperature of non-ferrous metal chlorides in the material.

3. The method of treating iron sulphidebearing material which comprises, bringing a chlorinating agent in Contact with said material at temperatures which progressively increas-e from approximately 300 C. to 550 C. as less chlorinated portions of the material comein contact with chlorinating agent.

4. The method of treating iron sulphidebearing material which comprises, passing ysaid material and a chlorinating agent through zones of different temperatures which progressively increase as less chlorinated portions of the ore are presented.

5. The method of treating irony sulphidebearing material which comprises, passing said material and a chlorinating agent in countercurrent relationship through different temperature zones, the temperature of said zones progressively increasing from the point of first contact of the chlorinating agent with said material.

6. rlhe method of treating iron sulphidebearing material which comprises, chlorinating one portion of a batch of said material to convert the iron sulphide to ferrie chloride, volatilizing said ferrie chloride whereby a substantially iron-free product is obtained in one portion of saidbatch, and contacting said ferrie chloride with another portion of said batch of material to chlorinate the same and obtain a concentrate of ferrous chloride.

7. The method of treating iron sulphidebearing material which comprises, chlorinating one portion of a batch of said material to convert the iron sulphide to ferrous chloride, contacting the ferrous chloride so obtained with chlorine to form ferrie chloride, volatilizing said ferrie Achloride whereby a product is obtained `in one portion of said batch containing the non-ferrous metal Colnpounds substantially free of iron, and contacting said ferric chloride with lanother portion of the batchof `said material to chlorinate the same. j

8. The method of treating iron sulphidebearing material. which comprises, chlorinating one portion of a batch of said material to convert the iron sulphide to ferrie chloride, volatilizing said ferrie chloride whereby a substantially iron-free product is obtained in one portionof said batch, and utilizing said ferric chloride to chlorinate another portion of said batch of material at a temperature below the boiling temperaturcs of chlorides of non-ferrous metals in the material whereby a concentrate of ferrous chloride is obtained.

9. The method of treating iron sulphidebearing material which comprises, contacting one portion of a batch of saidk material with a chlorinating agent to convert the iron sulphide to ferrous chloride at a temperature below the vboiling temperature of chlorides of non-ferrous metals in said material, contacting chlorine with the material rso obtained toconvert the ferrous chloride to ferric chloride, volatilizing said ferric chloride whereby a substantially iron-free product is obtained in said portion of the batch, and contacting said ferric chloride with another portion of said batch to chlorinate the same.

10. The method of treating iron sulphidebearing material which comprises, lpassing' said material through a reaction chamberin one direction, passing aV chlorinating agent through said chamber in the opposite'direction, maintaining such temperature at the point of first contact of said chlorinating agent with said material that the iron in the material is converted to ferrie chloride and Volatilized leaving a substantially iron-free residuepassing the mixture of chlorinating agent and ferric chloride in countercurrent flow with said material at a progressively increasing temperature whereby said material is chlorinated by said chlorinating agent and ferrie chloride forming a concentrate of ferrous chloride, and r-estricting the maximum temperature to a point below that at which chlorides of the non-ferrous metal constituents of said material will volatilize.

1l. The method of treating iron sulphidebearing material which comprises, passingr said material through a reaction chamber in one direction, passing a chlorinating agent through said chamber in the opposite direction, maintaining a temperature of not less than approximately 300 C. at the point of first contact of said'chlorinating agent with said material, whereby the iron in the material is converted to ferric chloride and volatilized and a substantially iron-free residue is obtained, passing the mixture of chlorinating agent and ferrieA chloride in countercurrent flow with said material at a progressively increasing temperature whereby said material is chlorinated by the action of said chlorinating agent and ferrie chloride forming a concentrate of ferrous chloride, and attaining a maximum temperature of not more than approximately 5500 C.

In testimony whereof we axour signatures.

i RAYMOND F. BACON.

HENRY T. HOTCHKISS, JR. 

